Rapid synthesis of uniform nano-sized silicalite-1 zeolite crystals under atmospheric pressure without wastes discharge

Zeolites have been widely applied in industrial processes, such as catalysis, adsorption, separation, while their syntheses generally suffer from environmental, safety, and efficiency issues. Herein, we report a fast synthesis of silicalite-1 zeolite crystals from fumed silica at 90 degrees C under atmospheric pressure. In the synthesis, all SiO2 is transformed to the silicalite-1 and the organic template rested could be reused cyclically. Therefore, the synthesis has neither liquid wastes nor solid wastes. Hence, it may be applicable for synthesizing a wide variety of zeolites and bears the potential for low-cost, environmentally friendly and highly efficient zeolite synthesis on an industrial scale. The silicalite-1 thus obtained has a uniform spherical morphology with the crystal size of 150 nm, and a high BET surface area (466.2 m(2)/g). The silicalite-1 crystals possess single-crystalline features, mesopores within the range of 3-30 nm, and abundant silanol nests. Due to its special physical and chemical properties, the silicalite-1 exhibited high catalytic activity in the probe reaction Beckmann rearrangement of cyclohexanone oxime.